Average Precipitation for Montana in September

The tables below give monthly averages for rainfall plus snowfall during September at cities, towns and parks in Montana.

Each place has a total for the amount of precipitation it usually receives this month. There is also a count of the number of days with wet weather, when precipitation amounts to 0.01 inches (0.25 millimetres) or more.

The precipitation totals are averages based on weather data collected from 1991 to 2020 for the US National Centers for Environmental Information.

You can jump to a separate table for each region of the state: Northwestern, Southwestern, South - Central and Eastern Montana.

Northwestern Montana

Average monthly precipitation in September
Days Place Inches Milli­metres
7 Cut Bank 1.1 27
7 Gibson Reservoir Dam 1.3 33
8 Kalispell 1.2 30
7 Libby 1.1 28
7 Missoula 1.0 24
7 Polson 1.2 30
6 Rogers Pass 1.7 42
9 Seeley Lake 1.2 30
10 West Glacier 2.0 50
8 Whitefish 1.3 32

Southwestern Montana

September averages for total rainfall plus snowfall
Days Place Inches Milli­metres
8 Anaconda 1.2 29
9 Bozeman 1.4 37
7 Butte 1.1 27
5 Dillon 0.9 23
6 Hebgen Lake Dam 1.6 40
6 Helena 1.0 24
6 Sula 1.3 32
6 Virginia City 1.2 30

South - Central Montana

Average amount of rain and snow in September
Days Place Inches Milli­metres
5 Bighorn Lake, Yellowtail Dam 1.7 42
7 Billings 1.4 35
10 Cooke City 1.7 44
9 Mystic Lake 2.0 52
7 Red Lodge 1.6 41

Eastern Montana

Precipitation totals for September
Days Place Inches Milli­metres
6 Culbertson 1.3 34
4 Elwell Lake, Tiber Dam 0.9 23
6 Fort Peck Lake Dam 1.1 27
7 Glasgow 1.1 27
7 Glendive 1.4 36
7 Great Falls 1.3 34
7 Havre City 1.1 27
9 Lewistown 1.4 35
7 Miles City 1.1 27
Reference

NOAA National Centers for Environmental Information (NCEI). Climate Normals.

Montana Precipitation
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